1967/1969 Bonnie Rebuild Desert Sled Project - Any Advice

Discussion in 'Vintage Classics' started by Sundance, Sep 15, 2021.

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  1. Sundance

    Sundance New Member

    Aug 2, 2021
    5
    3
    Arlington, VA
    Hi,

    I am new to the forum. I’ve some experience with motorcycles, first Bultaco Pursangs in the 1970’s, then on to BMW bikes. I had a K75S and rebuilt most of it. Then onto a K1300S, perfect shape and very fast and smooth - passed on to another rider in 2019.

    I’m in the northern part of Virgina, in the USA.

    Now those have gone and I’ve recently acquired a Triumph T120R. The bike is a 1967 T120R Bonneville frame (DU49062) and the engine from a 1969 T120R (EC 19971). It has been in storage for the past 30 years or so. It was rebuilt in about 1982, with a Routt 800cc big barrel kit. Apparently it wasn’t ridden much after then, the owner being in the military and moving around a bit while the bike was in storage.

    So I am trying to decide how to best approach this beast. The Amal monobloc dual carburetors are off the bike, and they have the numbers of “10 66” and “389/95” written on the intake flanges. So I am wondering where to get a rebuild kit for these carburetors - or perhaps new carburetors?

    Since the bike was rebuilt in 1982 and not ridden much after, I was thinking of just trying to rebuild the carbs and install them and do a good change of oil and fluids and such and trying to give the bike a go - that is see if I can get it running.

    The gas tank is rusted out so I need a new tank. I was looking for something simple, and saw some of the tanks for sale on eBay from India. I’ve heard these are not so great. Although I see they also have an alloy/aluminun tank that looks pretty nice.

    I am not trying to restore this bike, but just get it running and ridable - with a look to it being a bit more of a scrambler/desert sled style.

    So I am wondering if any of you might know the provenance of the carburetors and/or where to get a rebuild kit for them. Also, any suggestions or a replacement gas tank?

    Thanks for any advice. I imagine this forum has a number of threads that will have some great information. I will appreciate any of you having some advice or suggestions about the best places to go for parts and information.

    Thank you!
     
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  2. darkman

    darkman Crème de la Crème

    Oct 26, 2015
    5,755
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    Hi, 10 66 is Oct 66 built and 389 95 is a Amal 1" 3/16" mono block standard fit carb. There are plenty of dealers in the US that will sell rebuild kits or just gaskets like https://www.baxtercycle.com/ and they should have good used fuel tanks as well.
     
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  3. Iron

    Iron Guest

    Welcome Sundance, welcome indeed, we need a lot more right hand gear changers on here.
    I agree with darkman above, rebuild the carbs (parts are easily available, loads of good sites on that side of the pond - Mr Google will know lots) and get a good second hand or new tank (don't go for a "repairable" tank).
    Probably some of the best advice is available right here. But pictures are everything as well - give us a shufti (look). :)
     
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  4. Sundance

    Sundance New Member

    Aug 2, 2021
    5
    3
    Arlington, VA
    Well, it looks like my Amals have some more problems that anticipated. The slides are corroded and would need to be replaced as there is a hole in one of them. So as I put together the parts list of rebuilding and repairing the Amals, versus getting some new Mikunis or Amals and I wonder if in the long run I'd be better off with something new. EDE0697E-979B-447C-B6B8-AF551CEF4973_1_105_c.jpeg
     
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  5. darkman

    darkman Crème de la Crème

    Oct 26, 2015
    5,755
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    I would replace them :)
     
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  6. Iron

    Iron Guest

    Yep, agree, bin those
     
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  7. joe mc donald

    Subscriber

    Dec 26, 2014
    12,412
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    slough / burnham
    Nice little project and worth the effort. Also i think i would replace with the Mikuni's. Heard they were a better replacement than Amal's but no proof as i have never had any on a old classic. Amal still exist and still trade.
    Joe.
     
  8. Sundance

    Sundance New Member

    Aug 2, 2021
    5
    3
    Arlington, VA
    Thanks Joe. I'mm inclined toward the Mikunis at this point, particularly these from MAP - http://www.mapcycle.com/map0359-1-bonneville-69-72-30mm-mikuni-kit.html
     
  9. Sundance

    Sundance New Member

    Aug 2, 2021
    5
    3
    Arlington, VA
    OK, I have another question regarding carburetors with my bike. I was talking today to a work colleague who at one time converted his bonneville twin with 2 carbs to a single carb with a 2 into 1 manifold. I have done some looking on this and other forums and there is some instruction on this, however I can't seem to find where one might purchase this kind of manifold. I have seen where heads have been swapped out, twin for single carb heads. So I am wondering if anyone has made this change with the 2 into 1 manifold? Thanks.
     
  10. darkman

    darkman Crème de la Crème

    Oct 26, 2015
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    Single carbs make for a better ride on the street. The 67 T120 head has Delta inlet ports and i have never seen a inlet manifold for one as the ports are just wrong for that, fit a 64/68 TR6 head as it will swap over, 69 and 70 heads req different pushrod tubes.
     
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  11. Sundance

    Sundance New Member

    Aug 2, 2021
    5
    3
    Arlington, VA
    Thanks Darkman. Taking a look at the notes I wrote from the discussion I had with my colleague, I believe he had a 1970/72 500 motor, which may have had a head that allowed him to use the 2 into 1 manifold. I will stick with a twin carb setup for now as I'd like to use as much of the original bike that I can - unless a change will make things a lot easier or more efficient.
     
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  12. darkman

    darkman Crème de la Crème

    Oct 26, 2015
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    Yes 500 heads can use both twin or single carbs and manifolds as they are the same casting other than early heads use a smaller bolt/manifolds than later type :)
     
  13. Samsgrandad

    Samsgrandad Senior Member

    Dec 15, 2019
    427
    113
    Somerset
    As the bike has had a conversion to 800cc I would be reluctant to change to a single carb.
    You will be much better off keeping twin carbs
     
  14. Sundance

    Sundance New Member

    Aug 2, 2021
    5
    3
    Arlington, VA
    Thanks. I've decided this also. Now to choose which ones.
     
  15. Sundance

    Sundance New Member

    Aug 2, 2021
    5
    3
    Arlington, VA
    Speedo and Tach for 1967-1969 Bonneville - is there a way to install a digital speedometer and tachometer for a unit twin 67-60 vintage? I am wondering it anyone has installed a digital tachometer and speedometer, or a combination speedo/tach, on a vintage Triumph. I am not looking for a vintage look necessarily, just wondering if this is something that can be done - and if so what kind of work does it entail? Thanks.
     
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